In order to transport a watercraft having a jet propulsion system from one body of water to another, or between a body of water and a storage location, trailers that can be hitched to a motorized wheeled vehicle are often used. To receive the watercraft onto a trailer from water, typically, the trailer is backed down a ramp (either man-made or natural) at least partially into the water. The watercraft is then guided onto the trailer such that the watercraft sits on support structures of the trailer. Then the watercraft is secured to the trailer. Finally, the trailer and watercraft are pulled out of the water using the motorized vehicle.
In most such trailers, the watercraft is driven with the jet propulsion system while the watercraft is in deep waters towards the trailer standing on the shore at least partly in water, but sufficiently for part of the watercraft to float above the support structures. Then, while the watercraft is approaching the shallow waters near the shore, the jet propulsion system is set to idle speed or is fully switched off, such that the watercraft is propelled forward towards the shore by its own inertia. Once the watercraft reaches the proximity of the trailer, the driver aligns the watercraft onto the trailer by using the support structures which are adapted to engage a hull of the watercraft. These structures can consist of one or more beams or rollers. When the watercraft is engaged on the structure, and there is no rocks or other debris in the proximity of a stem of the watercraft on the bottom of the body of water, the driver usually applies throttle to move the watercraft further to the front of the trailer. Sometimes, when the watercraft is afloat above the support structures of the trailer, but there are rocks or other debris on the bottom of the body of water in the proximity of the stern of the watercraft, the driver may choose not to apply the throttle to advance watercraft further to the front of the trailer, rather the driver may choose to advance the watercraft manually to avoid having rocks or debris enter the jet propulsion system.
To set afloat the watercraft from a trailer, the trailer with the watercraft thereon is backed down a ramp (either man-made or natural) at least partly into the water, but sufficiently for the watercraft to float above the support structures. If there are no rocks or debris in the proximity of the stern of the watercraft, then the driver starts the jet propulsion system of the watercraft and applies some throttle in reverse to move the watercraft away from the trailer. If there are rocks or debris, then the watercraft is manually pushed away off the trailer. Finally, the trailer is pulled out of the water using the motorized vehicle.
The jet propulsion system usually has an intake located in a bottom of the hull, an intake grate covering the intake, an impeller, and a steering nozzle at the rear end of the hull. The impeller propels the water through the intake towards the nozzle and the nozzle discharges a high speed water stream in a direction selected by a driver, thus driving the watercraft. The intake grate is designed to prevent large rocks and other large debris from being sucked into the intake, along with propelled water, and damaging the impeller. The intake grate is optimized for stopping large rocks and large debris from entering the intake while allowing a sufficient volume of water to enter the intake to drive the watercraft.
An inconvenience arising during the receiving or the setting afloat of the watercraft onto or from the trailer, is that if the water level at a trailer rear portion is low, the jet propulsion system will suck into the intake, along with the propelled water, small and medium sized rocks, sand and other debris located on a bottom of a body of water below the intake. These small and medium sized rocks, sand and other debris will pass unhampered through the intake grate and damage the impeller of the jet propulsion system. Damaging the impeller may stop the jet propulsion system from functioning properly or functioning altogether. Repairing or replacing the impeller is costly and inconvenient. To avoid this problem, the watercraft is typically pushed off the trailer manually to launch the watercraft into the water. Often a strong push is required to push the watercraft off the trailer and far enough into deep water. Typically, to receive the watercraft onto the trailer, the watercraft is manually pushed onto the support structures of the trailer before securing the watercraft onto the trailer. Due to this, often, more than one person is required to launch or to receive the watercraft from or onto the trailer.
Therefore, there is a need for hampering and preventing small and medium sized rocks, sand and other debris from entering the intake of the jet propulsion system during the securing or the setting afloat of the watercraft onto and from a trailer in shallow waters or when the water level near the rear portion of the trailer is low.